Hello,
i'm using following construct:
<a:region renderRegionOnly="true">
 <h:form>
<a:commandLink value="Select All" action="#{someBean.selectAll}"/>
<a:commandLink value="Deselect All" action="#{someBean.deselectAll}"/>
<a:repeat ... var="var">
 <ui:include src="somepage.xhtml">
</a:repeat>
 </h:form>
</a:region>
<a:outputPanel ajaxRendered="true">
 <h:selectBooleanCheckbox value="#{var.selected}"/>
</a:outputPanel>
it might not work such way due to the specific of the iteration component in JSF. Re-render the whole repeat.